If you have hydraulic lifters, the rocker arms will have ball ends @ the push rods and will be screwed down 'tight'. Mechanical lifters will have ~0.015" clearance between the valve stem and rocker tip.
Hop-up tips -
Mill the head 0.100" for ~9.5:1 compression. Use a 244deg camshaft Got mine from Clifford
. Do a minimal clean-up bore, don't go for much added cu.in. Use a Clifford
single 4-bbl manifold (with manifold heat provision) w/small Holley or Edelbrock carb. Use Fenton cast iron split headers and dual exhaust. Convert it to electronic ignition ( I show a cheapie but effective way to adapt Chrysler electronics to the stock 235 distributor in my Journal
). Modify the engine for full flow oil filter like this
(go to 'Tech Tips', click on 'Full Flow Conversion', click on 'Chev 235/261 Full Flow' follow the directions). As you may have noticed I installed a 2004R OD tranny using a Langdon's Stove Bolt Engine Co.
adaptor so I won't be screaming @ 3000rpm @ 60mph.